On the problems of thermal analysis of solidification

Thermal analysis is a widely used method for metallurgical process control and investigation of cast alloy solidification. Thermal analysis involving thermocouples immersed in the molten metal is convenient to quickly obtain information on the solidification behaviour. The paper intends to elucidate the difficulties of thermal analysis induced by using one or several thermocouples, the shape of the analysed thermal field and the boundary conditions of the experimental set-up. Classical thermal analysis methods such the Newtonian thermal analysis and the Fourier thermal analysis differ because of the number of used thermocouples. The paper discusses the migration of the hot spot of a thermal field during solidification as well the migration of the thermocouples in complex shaped castings due to thermally induced stresses. Simulation and thermal analysis are made on both idealized 1-D cylindrical test geometry and common industrially used 3-D thermal analysis cup to compare different interpretation methods.